powerpc: Convert power off logic to pm_power_off

The generic Linux framework to power off the machine is a function pointer
called pm_power_off. The trick about this pointer is that device drivers can
potentially implement it rather than board files.

Today on powerpc we set pm_power_off to invoke our generic full machine power
off logic which then calls ppc_md.power_off to invoke machine specific power
off.

However, when we want to add a power off GPIO via the "gpio-poweroff" driver,
this card house falls apart. That driver only registers itself if pm_power_off
is NULL to ensure it doesn't override board specific logic. However, since we
always set pm_power_off to the generic power off logic (which will just not
power off the machine if no ppc_md.power_off call is implemented), we can't
implement power off via the generic GPIO power off driver.

To fix this up, let's get rid of the ppc_md.power_off logic and just always use
pm_power_off as was intended. Then individual drivers such as the GPIO power off
driver can implement power off logic via that function pointer.

With this patch set applied and a few patches on top of QEMU that implement a
power off GPIO on the virt e500 machine, I can successfully turn off my virtual
machine after halt.

Signed-off-by: Alexander Graf <agraf@suse.de>
[mpe: Squash into one patch and update changelog based on cover letter]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 30 insertions, 29 deletions

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 125c589eeef5..db0fc0c07568 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -659,6 +659,34 @@ static void __init pSeries_init_early(void)
         pr_debug(" <- pSeries_init_early()\n");
 }
 
+/**
+ * pseries_power_off - tell firmware about how to power off the system.
+ *
+ * This function calls either the power-off rtas token in normal cases
+ * or the ibm,power-off-ups token (if present & requested) in case of
+ * a power failure. If power-off token is used, power on will only be
+ * possible with power button press. If ibm,power-off-ups token is used
+ * it will allow auto poweron after power is restored.
+ */
+static void pseries_power_off(void)
+{
+        int rc;
+        int rtas_poweroff_ups_token = rtas_token("ibm,power-off-ups");
+
+        if (rtas_flash_term_hook)
+                rtas_flash_term_hook(SYS_POWER_OFF);
+
+        if (rtas_poweron_auto == 0 ||
+                rtas_poweroff_ups_token == RTAS_UNKNOWN_SERVICE) {
+                rc = rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1);
+                printk(KERN_INFO "RTAS power-off returned %d\n", rc);
+        } else {
+                rc = rtas_call(rtas_poweroff_ups_token, 0, 1, NULL);
+                printk(KERN_INFO "RTAS ibm,power-off-ups returned %d\n", rc);
+        }
+        for (;;);
+}
+
 /*
  * Called very early, MMU is off, device-tree isn't unflattened
  */
@@ -741,6 +769,8 @@ static int __init pSeries_probe(void)
         else
                 hpte_init_native();
 
+        pm_power_off = pseries_power_off;
+
         pr_debug("Machine is%s LPAR !\n",
                  (powerpc_firmware_features & FW_FEATURE_LPAR) ? "" : " not");
 
@@ -754,34 +784,6 @@ static int pSeries_pci_probe_mode(struct pci_bus *bus)
         return PCI_PROBE_NORMAL;
 }
 
-/**
- * pSeries_power_off - tell firmware about how to power off the system.
- *
- * This function calls either the power-off rtas token in normal cases
- * or the ibm,power-off-ups token (if present & requested) in case of
- * a power failure. If power-off token is used, power on will only be
- * possible with power button press. If ibm,power-off-ups token is used
- * it will allow auto poweron after power is restored.
- */
-static void pSeries_power_off(void)
-{
-        int rc;
-        int rtas_poweroff_ups_token = rtas_token("ibm,power-off-ups");
-
-        if (rtas_flash_term_hook)
-                rtas_flash_term_hook(SYS_POWER_OFF);
-
-        if (rtas_poweron_auto == 0 ||
-                rtas_poweroff_ups_token == RTAS_UNKNOWN_SERVICE) {
-                rc = rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1);
-                printk(KERN_INFO "RTAS power-off returned %d\n", rc);
-        } else {
-                rc = rtas_call(rtas_poweroff_ups_token, 0, 1, NULL);
-                printk(KERN_INFO "RTAS ibm,power-off-ups returned %d\n", rc);
-        }
-        for (;;);
-}
-
 #ifndef CONFIG_PCI
 void pSeries_final_fixup(void) { }
 #endif
@@ -796,7 +798,6 @@ define_machine(pseries) {
         .pcibios_fixup          = pSeries_final_fixup,
         .pci_probe_mode         = pSeries_pci_probe_mode,
         .restart                = rtas_restart,
-        .power_off              = pSeries_power_off,
         .halt                   = rtas_halt,
         .panic                  = rtas_os_term,
         .get_boot_time          = rtas_get_boot_time,